Warming Climate, Warming Oceans
Heat trapped by greenhouse gases is raising ocean temperatures faster than previously thought, concludes an analysis of four recent ocean-heating research studies. The results provide further evidence that earlier claims of a slowdown or hiatus in global warming over the past 15 years were unfounded.
“If you want to see where global warming is happening, look in our oceans,” said Zeke Hausfather, a graduate student in the Energy and Resources Group (ERG) and a co-author of the analysis. “Ocean heating is a very important indicator of climate change, and we have robust evidence that oceans are warming more rapidly than we thought.”
Ocean heating is a critical marker of climate change because an estimated 93 percent of the excess solar energy trapped by greenhouse gases accumulates in the world’s oceans. And unlike surface temperatures, ocean temperatures are not affected by year-to-year variations caused by climate events like El Niño or volcanic eruptions.
The analysis, published in January in Science, shows that trends in ocean temperature match those predicted by leading climate change models, and that overall ocean warming is accelerating.
The climate change models—assuming a “business as usual” scenario in which no effort is made to reduce greenhouse gas emissions—predict that the temperature of the top 2,000 meters of the world’s oceans will rise by 0.78 degrees Celsius by the end of the century. The thermal expansion caused by this bump in temperature will raise sea levels by 30 centimeters, or around 12 inches, on top of the sea level rise already caused by melting glaciers and ice sheets. Warmer oceans also contribute to stronger storms, hurricanes, and extreme precipitation.
— Kara Manke
Wolf Prize Goes to David Zilberman
David Zilberman, a professor in the Department of Agricultural and Resource Economics, has been awarded the 2019 Wolf Prize in Agriculture. The Wolf Prize is an international award granted by the Wolf Foundation in six categories; the prize Zilberman received is often referred to as the equivalent of a Nobel in agriculture. Zilberman was honored in recognition of his work developing economic models for fundamental problems in agriculture, economics, and policy.
"I am deeply honored to have been selected,” said Zilberman, who holds the Robinson Chair in the Department of Agricultural and Resource Economics. “This prize is a recognition of my entire community: my family, my collaborators, my teachers in Israel and Berkeley, the College of Natural Resources, and the uniquely supportive and inspiring Berkeley campus."
Zilberman is one of the most cited scholars in agricultural, environmental, and resource economics. During the 1980s, his work served as the basis for several projects on the adoption of modern irrigation technology and computers in California agriculture. These studies demonstrated that farmers adopt new technologies when it makes economic sense and that extreme events, such as droughts or high prices, can trigger changes in farming practices. During the early 1990s, his research on pesticide economics and policy made the case against policies that called to ban pesticides, and advocated instead for smart policies that take advantage of the vast economic benefits that pesticides generate while using incentives to protect against environmental side effects.
Inequalities in Solar Energy Access
By combining remote sensing data from Google’s Project Sunroof with census tract information, CNR researchers have discovered significant racial disparities in the adoption of rooftop solar photovoltaic systems in the United States. Their findings were published in January in Nature Sustainability.
“Our work illustrates that while solar can be a powerful tool for climate protection and social equity, biases and barriers to access can dramatically weaken the social benefit,” said co-author and ERG professor Dan Kammen.
The researchers found that among households with the same median income, black- and Hispanic-majority census tracts had fewer rooftop solar arrays installed than areas with no majority ethnic group, by 69 and 30 percent, respectively. White-majority census tracts had 21 percent more rooftop solar arrays installed.
When correcting for homeownership, black- and Hispanic-majority census tracts had fewer rooftop solar arrays installed by 61 and 45 percent, respectively, compared with no-majority tracts, while white-majority census tracts had 37 percent more arrays installed.
“Advances in remote sensing and in ‘big data’ science have allowed us to chart who gets to benefit from the solar energy revolution and, therefore, to think more deeply about the effectiveness of current policies and approaches to accelerate solar photovoltaic deployment,” said Sergio Castellanos, an ERG postdoctoral scholar and co-author on the study.
Invisible Pathogens Endanger Ecological Restoration
Laura Sims, a researcher in the Garbelotto lab, examines Phytophthora-infected coffeeberry plants at a restoration site.PHOTO: William Suckow
In 2014, the California Department of Food and Agriculture reported an alarming discovery: native wildflowers and herbs grown in nurseries and then planted in ecological-restoration sites around California were infected with Phytophthora tentaculata, an exotic plant pathogen that causes root and stem rot.
The presence of this pathogen in restoration sites raised the frightening possibility that ecological restoration, rather than returning disturbed sites to their natural state, may actually be introducing deadly plant pathogens into the wild. New work by a team of scientists in the College of Natural Resources shows just how widespread and harmful the threat of pathogens from restoration nurseries may be.
Led by Matteo Garbelotto, a Cooperative Extension specialist and adjunct professor in the Department of Environmental Science, Policy, and Management, the team surveyed native-plant nurseries in Northern California and found that many harbored Phytophthora pathogens. What’s more, strains of the pathogens from the native-plant nurseries were shown to be at times more aggressive than strains found in the wild, and some of them are rapidly developing resistance to the fungicides that can be used to control them, the researchers found. Results from the team’s work on this topic appeared last December in PLOS One, Plant Pathology, and California Agriculture.
Working with restoration nurseries around the state, the team helped implement new management practices to try to limit the spread of disease without using fungicides. These guidelines, which include careful management of water runoff and soil to avoid cross contamination, reduced the prevalence of disease to nearly zero a year after implementation.
— Kara Manke
$9.2 Million to Tackle Liver Disease
A research team co-led by Anders Näär, a professor in the Department of Nutritional Sciences and Toxicology, has received $9.2 million from the Novo Nordisk Foundation to research new treatment therapies for nonalcoholic steatohepatitis (NASH).
NASH is a progressive subtype of nonalcoholic fatty liver disease, which is the most common type of chronic liver disease worldwide. While the cause of NASH is unknown, the disease is associated with obesity and metabolic syndrome and can progress to liver failure and hepatocellular carcinoma.
Näär’s team will study microRNAs—snippets of noncoding RNAs that can act as crucial regulators of human physiology and disease—to develop microRNA-targeted drugs for NASH.
When Policy Numbers Don’t Add Up
When it comes to fuel economy standards, there is no single accepted procedure for arriving at the miles-per-gallon targets that automakers must hit. Rather, analysts use any of multiple parameters and tactics to calculate the potential economic and environmental impacts of fuel efficiency levels.
So when James Sallee, an assistant professor of agricultural and resource economics, first saw that the Obama-era standards had flunked the current administration’s 2018 cost-benefit analysis—which was subsequently used as justification for rolling back the stricter standards—he didn’t think much of it. Analysts had correctly referenced some of his published research findings, and they were working with an ambiguous process.
After digging into the analysis further, however, Sallee went on to co-write, with 10 academic colleagues, a commentary in Science that raises serious questions about the scientific validity of the proposed rule change. That’s because the Environmental Protection Agency and the National Highway Traffic Safety Administration—the agencies that govern fuel standards—arrived at a completely different conclusion from their predecessors’ using exactly the same data.
“So we wanted to know, what’s the difference?” Sallee said. “When we dove into how they changed the model, we disagreed with almost all of the ways the major changes were implemented.” The team uncovered mistakes in math and in the application of economic theory.
Because of errors like those as well as other actions—such as the abandonment of the Paris Agreement and the Clean Power Plan—Sallee noted, scientists are increasingly concerned about a perceived sidelining of science in the Trump administration’s decision-making processes. “It’s unambiguously distressing. In the long run, that’s the biggest concern, rather than any individual policy.”
Sallee said that the real litmus test will be whether federal analysts address the errors. If they don’t, he added, the Science article forms part of a “trail of concern”—formal scientific objections that could potentially be used by future leadership to revoke the current policy decisions.
— Anne Brody Guy
Private Pollution Monitors:
Gimmick or Game Changer?
State and federal government agencies have traditionally been the primary source of air quality data, but the high cost of monitoring has limited the scope of publicly available information. In the United States there are fewer than 1,000 regulatory-grade compliance monitors measuring PM2.5—the very small particles that pose significant health risks.
There can be big differences in the levels of pernicious local pollutants like PM2.5 over short distances, so the sparseness of this monitoring network really matters for anyone looking to understand or limit their exposure. Recently, though, low-cost, consumer-grade sensors from companies like PurpleAir have started to fill some big information gaps.
Here in California, private citizens have deployed more than three times as many air pollution sensors as the government agencies charged with monitoring our air quality. Although the technology is not as reliable as regulatory-grade monitors, our colleagues at the Lawrence Berkeley National Laboratory have found that it works surprisingly well. And once connected to Wi-Fi, privately owned PurpleAir devices link up with a global network that displays their data on a map in real time for all to see. This crowdsourcing of air quality information marks an important shift away from the status quo and opens the door for citizen scientists who want to know more about the air they breathe.
During the Camp Fire in November 2018, Northern California was clouded with smoke for over a week. Outdoor particulate concentrations reached dangerous levels. Using real-time feedback from our PurpleAir monitor, my family and I started experimenting with adaptation. This little sensor made invisible air pollution visible to us, and we were able to identify and make adjustments—like replacing our furnace filters and constantly running the fan—that measurably improved our indoor air quality.
A 2017 California law, AB 617, mandates that community-level air monitoring be put in place by mid-2019 to improve conditions in communities that are disproportionately affected by outdoor air pollution. To keep implementation costs manageable, low-cost sensors will likely play an important role. These monitors aren’t a perfect substitute for regulatory-grade ones, but they could be important complements. If well-crafted policy implementation and community mobilization can catch up with innovations in sensor technology, these cool gadgets could become a real game changer.
Meredith Fowlie is an associate professor in the Department of Agricultural and Resource Economics. A longer version of this article originally appeared on the blog of the Energy Institute at the UC Berkeley Haas School of Business.